Mattress for preventing bedsores

ABSTRACT

A mattress is constructed of foam having a 50% compression deflection pressure equal to the body weight of an average patient divided by his projected body area and a thickness in excess of his body depth, to prevent bedsores by providing a moldable surface which spreads support to a great area of the patient&#39;&#39;s body. The mattress surface supporting the patient is subdivided into a plurality of individual load bearing units to provide lateral give to the mattress. A water proof cover sheet fits over the mattress and includes means for tightening the cover about the mattress to provide a firmer mattress for maneuvering the patient.

United States Patent 11 1 Blair 1 MATTRESS FOR PREVENTING BEDSORES [75]Inventor: E. Allan Blair, Princeton, NJ.

[73] Assignee: Medic-Ease Corporation, Princeton,

[22] Filed: Mar. 29, 1972 [21] Appl. No.: 239,219

[451 July 8,1975

7/1970 Cohen 5/361 B 4/1971 Weinstein 5/348 5 7 ABSTRACT A mattress isconstructed of foam having a 50% compression deflection pressure equalto the body weight of an average patient divided by his projected bodyarea and a thickness in excess of his body depth, to prevent bedsores byproviding a moldable surface which spreads support to a great area ofthe patients body. The mattress surface supporting the patient issubdivided into a plurality of individual load bearing units to providelateral give to the mattress. A water proof cover sheet fits over themattress and includes means for tightening the cover about the mattressto provide a firmer mattress for maneuvering the patient.

8 Claims, 3 Drawing Figures 1 MATTRESS FOR PREVENTING BEDSORESBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to a mattress for preventing the formation of decubitus ulcersor bedsores as they are popularly known.

2. Description of the Prior Art Decubitus ulcers or bedsores are acommon problem among people who are paralyzed, in a coma, or chronicallybedridden, e.g., I to of all bedridden patients develop bedsores. Theyare a major economic problem among individuals in the categories aboveand they cause great incapacitation and even death to the people whosuffer from them. Generally, bedsores occur over the bony protruberancesof the body, such as the sacrum and shoulder blades on the posterior,the iliac crest on the anterior, the greater trochanters on the sides,the knees on the legs and the heels on the feet, i.e., areas where theskin is compressed between hard bone and a hard mattress.

Many methods have been used to treat or prevent bedsores. Turning thepatient every 2 hours to allow reestablishment of circulation over thebony protruberances is generally used, but this method increases thework load of the nursing staff and interrupts the patients rest.Furthermore, in some cases it is not possible to turn a patient becauseof specific injuries. Sheepskins are often used to allow ventilation andminimize pressure but this creates severe cleaning problems, since thedecubitus ulcers often bleed or drain, and patients who have them areoften incontinent. This means that the sheepskins must be launderedfrequently and they are very difficult to launder.

Other devices attempt to alleviate bedsores. One such device is anair-mattress in which the air pressure is applied alternately toadjacent tubes. This transfers the pressure from one spot to anotherallowing circulation to be reestablished. This method has thedisadvantage of requiring a device for providing an alternating airsupply.

A device for providing a soft supporting surface is the water mattress.However, water mattresses have the disadvantage of being extremelyheavy, cold, difficult to fill, prone to leakage and their softnessmakes it difficult to move the patient about on their surface. Further,when a patient lies in a prone position the cover of the mattress closesaround his face causing the patient psychological distress and limitinghis free breathing. Also, catheters, which may be attached to a patient,will not drain freely because the tube must rise to pass over the edgeof the water mattress. These problems make the water mattress the leastused solution to bedsores, even though it is the most effective inproviding a soft surface.

SUMMARY OF THE INVENTION This invention concerns a mattress which hasall the desirable properties of the water mattress for the prevention ofdecubiti, without any of its liabilities. lt consists of a mattress of apolyurethane or similar foam, having a 50 percent compression deflectionpressure equal to the users weight divided by the projected area of hisbody in contact with the mattress and a thickness greater than the depthof his body. This is an exceedingly soft foam, having an RMA firmness of13 to 23.

Normally, mattresses are made with an RMA firmness of 23 to 35. If amattress having an RMA firmness below 23, is made in the normalthickness of 4 to 6 inches, the person lying on it finds ituncomfortable because he sinks in to the point where he feels the hardsupports for the mattress. On the mattress described in this invention,however, the hard support for the mattress is not felt because theperson lying on it does not sink in to more than three-fourth of itsdepth.

A foam mattress having a total thickness of 12 inches may be incised ina pattern to a depth of about 4 inches to provide further softness anddecrease resistance to lateral movement. If the incisions are too deepor too close together, the cut edge of the foam curls into them andforms ridges. Thus, the incisions should be about 7 inches apart.Further, no incision should be centered on the longitudinal axis of themattress, since the patient tends to settle into such an incision thuslosing the support of the mattress. It is also preferred that theincisions not reach the edge of the mattress and no incisions arenecessary in the head area while the incised pattern may be smaller inthe foot area. The head area is cut dowh by a depth of about 4 inches toa thickness of about 8 inches, to allow greater comfort for a patient inthe prone position, to allow the neck to remain in a neutral position,and to avoid having the face buried in the mattress.

At the area of the hips, a notch about 7 inches wide and 6 inches deepis cut into the unincised edge of the mattress up to the incised area. Acatheter tube can be placed in that notch, thereby allowing it to drainfreely when the patient is in the prone position.

Such changes in the surface of the mattress as the cut-out head andcatheter tube channels cannot be made on a water mattress.

With such a mattress, in accordance with the invention, the patientsbody sinks very deeply into the mattress, with his weight uniformlydistributed over the length of his body rather than concentrated on hisbony protruberances. Thus, paraplegics may lie on this mattress eitherprone or supine for unlimited time, without exhibiting any erythema overthe bony protruberances. Since erythema is the invariable precursor ofdecubitus ulcers, it is clear that this mattress eliminates the need toturn the patient to prevent decubiti, when the patient is in the proneor supine position and requires no pre ventative methods other than theusual appropriate good nursing practices.

A further aspect of the invention is a waterproof cover for themattress, which is loose fitting and soft and pliable enough so that thepatients weight is sup ported solely by the mattress and not by thecover. The cover has straps attached to and extending from one sidewhich go under the bed frame, and fasten into clamping buckles which aremounted on straps attached to the other side of the cover. Thus, thiscover serves two functions: It protects the foam mattress from beingsoiled by the patient and, by tightening the straps, the mattress may bemade firm so that the patient can be easily turned or moved.

Tightening can be either accomplished manually or a mechanical devicemay be used which consists of a rod or shaft running the length of thebed, around which the straps are looped. The shaft can be rotatedmechanically, thereby tightening the straps and cover. For manualoperation, the straps are simply pulled tight through the clamp bucklesby hand.

To loosen the cover again so that the mattress recovers its normalsoftness, the buckles are either released manually or the shaft rotatedto its normal position depending upon the tightening method.

The mattress as described above in accordance with the invention alsoserves the purpose of allowing skin grafts to heal while the patient islying on them and contributes greatly to comfort in orthopedic andsurgical cases in which localized pressure on injured tissue or bonescauses discomfort. It may also aid in muscle relaxation.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiment of theapplicant's inven tion will now be described with reference to thedrawings in which:

FIG. 1 is a top view of a mattress in accordance with the inventionshowing the cover sheet partially removed;

FIG. 2 is a front view of the mattress of FIG. 1 shown in place on ahospital bed from the top end thereof showing one method of tighteningthe cover; and

FIG. 3 is a bottom view showing a second method of tightening the cover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, amattress I is illustrated in general which may have appropriatedimensions to serve, for example, as a hospital bed. The mattress isformed of a plastic foam such as polyurethane which has known softnessand resilience, The foam is chosen for its firmness so that at 50percent deflection it will produce an upward force substantially equalto the downward force exerted by the weight of the average patient.Moreover. since the mattress is formed of a pad of plastic foam materialdeeper than a patients body. e.g., 12 inches in thickness, it moldsitself to the patients body thereby supporting the maximum area of hisbody and relieving the usual supporting surfaces, such as the sacrum,hips and heels, iliac crest and knees. from supporting the entire bodyweight. For an average patient having a body weight of 150 pounds, and abody area in contact with the mattress of 500 square inches whichaverage weight and body dimensions are provided in the publication TheMeasure of Man. Human Factors in Design" by Henry Dreyfuss, 2d ed. pub.1967 by The Whitney Library of Design, 18 East 50th St., New York, NY.10022, for an average pressure of about 0.3 psi exerted by the body, themattress should have a 50 percent deflection firmness of 0.65 to 1.2psi, which corresponds to an initial Rubber Manufacturers Associationfirmness value of 13 to 23. Such a foam will soften in use to correctvalues of firmness.

The above mentioned foam is not used in conventional mattresses since itis found that in the conventional range of mattress thickness, 4 6inches, a firmer foam is necessary to avoid contact between the mattressusers body and the supporting surface for the mattress.

The mattress 10 is subdivided into a plurality of load bearing units 12which may be squares having an edge dimension of 7 inches. These squareare defined by incisions 14 formed in the upward surface of mattress itwhich, in turn, may be approximately 4 inches deep. The load bearingunits 12 have lateral give, due to the incisions l4, and thus when apatients body moves latorally the shearing effect between his skin andtissues caused by the frictional resistance of the supporting surface tolateral movement is greatly reduced.

Since the incisions 14 would produce a structural weakness if continuedto the sides of mattress 10, the incisions stop before all side areas 16of the mattress. At the level of the hips a notch 43 at least 6 incheswide and 6 inches deep is cut into the side area extending at. the wayto the incised area (on each side of the mattress 10). These notchesform a path for the catheter tube, thereby allowing the cather tube todrain freely when the patient is in the prone position. Further. toprevent the tendency of a patient to fall into a slit arranged along thecentral axis of mattress 10, there is no longitudinal slit along thelength of axis 18.

The feet of a bed ridden patient under the heels due to the highpressures caused by body movements, are particularly subject to theshearing effect described above. Thus, in region 20 which corresponds tothe foot of mattress 10, a smaller grid pattern is formed having squareload bearing units 22 with an edge dimension of about 3% inches.Further. since bedsores are rarely a problem on the head. the gridpattern at the head area 21 may be discontinued without harm to theinvention.

The head area 21 of the mattress 10 as shown in FIGS. 1 and 2 is cutdown across the entire width of the mattress 10 to a depth of about 4inches. This leaves a thinner section of 8 inches of the mattress at thehead area 21 and allows the patients neck to be in a neutral positionwhen he is lying prone. preventing his head from being sunken into themattress, as it is in a water mattress.

'Ihe mattress 10 described above is covered by a cover 24 of waterproofsoft material such as 1.1 ounces per square yard of ripstop nylon coatedwith polyurethane, vinyl or rubber. As can be seen in FIG. 1, the cover24 extends beyond all the edges of mattress 10 so that when the patientsinks deeply into the mattress the cover is not drawn tight on themattress. In addition, straps 26 are attached at intervals of, forexample. 10 inches. along one edge of the cover starting 18 inches fromthe head of the mattress. and registering straps 28 having buckles .30are arranged at the corresponding places at the other side of the cover.

As is seen in FIG. 2, the straps 26 and 28 may be arranged under theside rails 32A and 32B of a hospital bed 34 and drawn together withbuckles 30 to provide a firmer surface 36 upon which a patient may bemore easily turned for bathing. The straps 26 may be alternativelywrapped around a shaft 38 as shown in FIG. 3. Thus. by rotating shaft 38all the straps 26 may be tight ened or loosened in unison. Shaft 38 maybe rotated by hand crank 40 shown in FIG. 2 or by other known means suchan electric motor 41 and transmission 42 shown in FIG. 3.

While the above description fully covers the preferred embodiments ofthe applicants invention, many modifications may be made within thescope of this invention. Thus. for example. the surface of mattress l0Jl'tjf, .ic contoured to fit a patients body.

' rot is claimed is: i. t mattress for the prevention of bed sores in auser cinnprising a unitary member made of resilient foam having a.thickness greater than the thickness of an average users body and havingload-bearing properties wherein a 50 percent compression deflectionpressure is substantially equal to the user's body weight divided by hisbody area in contact with the mattress, said mattress being subdividedupon its surface into a plurality of individual load-bearing unitswhereby said mattress absorbs the downward weight and lateral movementof the user's body to protect said users body from contact with hardsurfaces and from localized high pressure over the bony protuberances, acover of flexible, waterproof and soft but strong fabric which is sizedto cover the top and overlap, all edges of said mattress which is looseenough that it is not pulled tight when the user sinks deeply into themattress, means for drawing at least two opposed edges of the covertightly about the mattress so that the mattress is rendered firm enoughto easily move a patient disposed thereupon, said drawing means includesa plurality of straps affixed to one edge of said cover and a pluralityof buckles affixed to an opposed edge of said cover, said straps beingextended thereunder, a shaft disposed beneath said mattress, said strapsbeing wrapped about said shaft and means for rotating said shaft wherebythe tension upon said straps may be adjusted in unison.

2. The mattress recited in claim 1 wherein said rotating means includesan electric motor.

3. A mattress for the prevention of bed sores on a user comprising aunitary member made of resilient foam, having a thickness greater thanthe thickness of an average users body and having load-bearingproperties wherein a 50 percent comparison deflection pressure issubstantially equal to the user's body weight divided by his body areain contact with the foam, said foam absorbing and distributing thedownward weight of the user's body by allowing the body to sink deeplyinto the foam and avoiding localized high pressure being applied to bodyprotuberances, and means for lifting the user's body lying on the foamincluding a cover of pliable material which rests on the surface of thefoam beneath the users body without being secured to the foam and beingloose enough so that it is not pulled tight when the user sinks deeplyinto the foam, said user being supported solely by the foam during use,and means attached to the cover for drawing at least two opposed edgesof the cover apart to make the cover taut while the user is disposedthereupon without applying any force to the foam beneath the user toeasily move the user sunk in the foam.

4. The mattress recited in claim 3 wherein said drawing means comprisesa plurality of straps affixed to one edge of said cover and a pluralityof buckles coupled to an opposed edge of said cover.

5. The mattress recited in claim 3 wherein said cover is waterproof,soft but strong fabric.

6. The mattress recited in claim 3, wherein said cover tautening meansincludes a plurality of straps and means for tightening the straps.

7. The mattress recited in claim 6 wherein said strap tightening meansincluding a shaft and means for rotating said shaft.

8. The mattress recited in claim 6 wherein said cover tautening meansfurther includes buckles, said straps being extended under said foam.

1. A mattress for the prevention of bed sores in a user comprising aunitary member made of resilient foam having a thickness greater thanthe thickness of an average user''s body and having load-bearingproperties wherein a 50 percent compression deflection pressure issubstantially equal to the user''s body weight divided by his body areain contact with the mattress, said mattress being subdivided upon itssurface into a plurality of individual load-bearing units whereby saidmattress absorbs the downward weight and lateral movement of the user''sbody to protect said user''s body from contact with hard surfaces andfrom localized high pressure over the bony protuberances, a cover offlexible, waterproof and soft but strong fabric which is sized to coverthe top and overlap, all edges of said mattress which is loose enoughthat it is not pulled tight when the user sinks deeply into themattress, means for drawing at least two opposed edges of the covertightly about the mattress so that the mattress is rendered firm enoughto easily move a patient disposed thereupon, said drawing means includesa plurality of straps affixed to one edge of said cover and a pluralityof buckleS affixed to an opposed edge of said cover, said straps beingextended thereunder, a shaft disposed beneath said mattress, said strapsbeing wrapped about said shaft and means for rotating said shaft wherebythe tension upon said straps may be adjusted in unison.
 2. The mattressrecited in claim 1 wherein said rotating means includes an electricmotor.
 3. A mattress for the prevention of bed sores on a usercomprising a unitary member made of resilient foam, having a thicknessgreater than the thickness of an average user''s body and havingload-bearing properties wherein a 50 percent comparison deflectionpressure is substantially equal to the user''s body weight divided byhis body area in contact with the foam, said foam absorbing anddistributing the downward weight of the user''s body by allowing thebody to sink deeply into the foam and avoiding localized high pressurebeing applied to body protuberances, and means for lifting the user''sbody lying on the foam including a cover of pliable material which restson the surface of the foam beneath the user''s body without beingsecured to the foam and being loose enough so that it is not pulledtight when the user sinks deeply into the foam, said user beingsupported solely by the foam during use, and means attached to the coverfor drawing at least two opposed edges of the cover apart to make thecover taut while the user is disposed thereupon without applying anyforce to the foam beneath the user to easily move the user sunk in thefoam.
 4. The mattress recited in claim 3 wherein said drawing meanscomprises a plurality of straps affixed to one edge of said cover and aplurality of buckles coupled to an opposed edge of said cover.
 5. Themattress recited in claim 3 wherein said cover is waterproof, soft butstrong fabric.
 6. The mattress recited in claim 3, wherein said covertautening means includes a plurality of straps and means for tighteningthe straps.
 7. The mattress recited in claim 6 wherein said straptightening means including a shaft and means for rotating said shaft. 8.The mattress recited in claim 6 wherein said cover tautening meansfurther includes buckles, said straps being extended under said foam.